<?php
$sessionId = -1;
session_start();

if(isset($_SESSION["id"]))
{
  $sessionId = $_SESSION["id"];
}
else
{
  $_SESSION["caller"] = $_SERVER['PHP_SELF'];
  header("Location: login.php");
  exit();
}
$isAdmin = false;
if(isset($_SESSION["isAdmin"]))
  $isAdmin = $_SESSION["isAdmin"];
?>